I have been doing a comparison of my manual calibration in PI using ImageCalibration on the QHY183 (mono CMOS) with the PixInsight BPP and WBPP scripts and found some anomalies which could cause unexpected issues. I have posted this in bugs, as I would expect the two scripts to implement fundamental calibration the same, using the same settings.
In each case I processed a single light file, so I could easily compare calibration results (no light integration involved)
In summary, in my simple experiment it appears that BPP and WBPP are not calibrating lights using the same rules (using equivalent settings).
I have a master calibration library and for the experiment I had already created Master Darks, Bias and Flats. Master Darks and Bias are simple stacks and Master Flats are calibrated with a matching Master Dark and the usual normalisation and integration. No bias subtraction or scaling was involved. (I use refractors and flats are good across several sessions)
Loading these masters, in BPP, I checked the corresponding master boxes, unchecked optimize dark frames, unchecked CFA and checked calibrate only.
Comparing my manual light calibration method (which only calibrates with Master Flats and Master Darks) with BPP created identical results. Interestingly, if I cleared the Master Bias file from BPP, the result was still identical (checked with image analysis tools)
I loaded up the same files (Master Flat, Dark, Bias and light) and settings in the WeightedBPP and disabled the additional setting 'calibrate master darks' too. The result was awful, heavily clipped to black.
If I remove the Master Bias and run WBPP script again, I achieve the same result as the manual method / BPP script. I started afresh, repeated the comparison and got the same result.
This is a surprising and potentially significant result - which indicates that there are more differences between BPP and WBPP than just image weighting. As it appears right now, I would defer to BPP. One possible explanation is that WBPP bias-subtracts a master dark but BPP does not?
There is no documentation, so I tried to decipher the batch scripts but I'm more familiar with C#.
These scripts are useful for many, especially those starting out and it would be useful to understand them better and correct any potential issues.
If it helps, I put my masters and a light frame into dropbox: https://www.dropbox....ZWTvfM9lta?dl=0
In each case I processed a single light file, so I could easily compare calibration results (no light integration involved)
In summary, in my simple experiment it appears that BPP and WBPP are not calibrating lights using the same rules (using equivalent settings).
I have a master calibration library and for the experiment I had already created Master Darks, Bias and Flats. Master Darks and Bias are simple stacks and Master Flats are calibrated with a matching Master Dark and the usual normalisation and integration. No bias subtraction or scaling was involved. (I use refractors and flats are good across several sessions)
Loading these masters, in BPP, I checked the corresponding master boxes, unchecked optimize dark frames, unchecked CFA and checked calibrate only.
Comparing my manual light calibration method (which only calibrates with Master Flats and Master Darks) with BPP created identical results. Interestingly, if I cleared the Master Bias file from BPP, the result was still identical (checked with image analysis tools)
I loaded up the same files (Master Flat, Dark, Bias and light) and settings in the WeightedBPP and disabled the additional setting 'calibrate master darks' too. The result was awful, heavily clipped to black.
If I remove the Master Bias and run WBPP script again, I achieve the same result as the manual method / BPP script. I started afresh, repeated the comparison and got the same result.
This is a surprising and potentially significant result - which indicates that there are more differences between BPP and WBPP than just image weighting. As it appears right now, I would defer to BPP. One possible explanation is that WBPP bias-subtracts a master dark but BPP does not?
There is no documentation, so I tried to decipher the batch scripts but I'm more familiar with C#.
These scripts are useful for many, especially those starting out and it would be useful to understand them better and correct any potential issues.
If it helps, I put my masters and a light frame into dropbox: https://www.dropbox....ZWTvfM9lta?dl=0